Segmental grinding wheel



Oct. 26, 1926. 1,604,943

T. LARssON- SEGMENTAL GRINDING WHEEL Filed Feb. 9, 1925 2 Sheets-Sheet :1

I INVENTOQR Oct. 26, 1926. 1,604,943

T. LARSSON SEGMENTAL GRINDING WHEEL Filed Feb- 9. 1925 2 Sheets-Sheet 2 WITNESSES INVENTOR U/zure iarsson 3 H MM v Patented Oct. 26, 1926.

UNITED STATES TTIUBE LARSSON, or woRcEsTnn; MASSACHUSETTS, sssrenon To 'NoRToN 001mm, or WORCESTER, MASSACHUSETTS, A CORPORATION or MASSACHUSETTS.

SEGMENTAL GRINDING WHEEL.

Application filed February 9, 1925. Serial m. 7,769.

This invention relates to abrasive wheels,

and more particularly to a segmental grind ing wheel of artificial abrasive bonded, with an appropriate binding agent, such for ex:

5.ample, as a ceramic material, and which is particularly adapted for grinding wood pulp. The inventionhas for its object the provision of certainexpedients which tend to eliminate many of the dilficulties encountered in the manufacture and use of grinde ing wheels of this type In the' manufacture of paper from wood it has heretofore been customary to grind logs with an abrasive wheel of natural sandstone, or abrasive granules bonded with cold set cement, as an abrasive element. The cement bonded stones are ordinarily used onlyin cold grinding processes, whereas the proc-' on the cutting face. This procedure, which is known to the trade as hurting the stone,

' placed side by side, but the differential exv is wasteful of the expensive stone and consumes valuable time which should be devoted to grinding pulp. Moreover, theridges on such a. soft wheel do, not stand up under the severe strain of grinding and must be renewed at frequent intervals; hence the stone is short-lived. l

Various efforts have beenmade to employ a grinding wheel of the type used in the metal industry but heretofore thishas not proven successful. A stone as large as is normally required for grinding wood pulp efficiently is diificult to manufacture, and the. firing of such a large piece in a commercial; kiln is likely to produce a wheel not prop-- ergly annealed and therefore "susceptible to.

breakage during use. An attempt has beenmade to use stones madeup of disc sections pansio'n of such a wheel structure and its metal mounting may. introduce strains into the wheel likely to cause breakage' Heretofore, im the manufacture of seg- The cement bonded stones aremental pulp grinding wheels it has been customary to assemble the abrasive segments upon a rotatably mounted drum by sliding the abrasive segment in between two wedge blocks or wedge shaped members properly spaced around the periphery of the drum.

- These wedge shaped members have been positioned in various ways upon the drum surface, such for example, as parallel to the axis of the drum, or circumferential with the drum. The segments wereflprovided with a bottom portion properly shaped to fit against and be secured to the drum by these wedge I shaped members. The crevice between adj acent segments was then supplied with an appropriate cementitious material from the exterior of the grinding wheel. It was prac- ,ticallyimpossible to properly support the segments around the positioning members and the drum surface. These wheels have not been entirely satisfactory because the abrasive segments frequently crack, resulting in the early deterioration of the grind ing wheel. Moreover, in general, the heretofore customary method of assembling the segments upon the drum is cumbersome and tedious.

I have discovered that the life of a pulp grinding wheel may bevery materially increased by properly supporting the abrasive segments on the drum. This may be accomplished byappropriately supplying a cementitious material around the abrasive segments. I may employany appropriate cem-' entiti'ous material, such for example, as molten sulphur, Portland cement, metallic lead, or Babbitt metal. Preferably, I employ a cementitious material which will I wear away, when hardened, at substantially I the same rateas the abrasiveA/segments. have obtained most satisfactory results with an alloy composed for the most part of tin and containing relatively small ainounts of antimony and copper. The present invention contemplates th'e provlsion of certain means whereby the abrasive segments may be" assembledlon secured to the drum with ccfmparative ease, and whereby a cementitious material may be, appropriately supplied around the segments to properly support the same on the drum. In accordance with the invention, I provide a rotatably mounted drum having'openings lso shaped andarran'ged that a bottom or re- 7 H duoed portion of the abrasive" segments may be inserted therein and permit supplying a segment and the wall of the lower or recementitious material from the interior of duced part of each opening may be inclined I the drum to properly support and secure the or ,have an irregular shape. By irre ular, l I

segments to the drum, the top surface of the mean a surface having indentations orprosegments forming a substantially cylindricalifjections, or'both.

grinding surface. The upper parts of the openings may be The drum mayhave openings ;of any one constructed either integral with the drum or of varioiis forms. Thus, the openings may may be detachable therefrom and are so be tapered to the interior of the drum and shaped and arranged in accordance with the the bottom or reduced portion of the abrainvention to best suit the requirements of 75 sive segment placed therein, and properly the particular pulp stone. In general, the

- placed, and lower or inner parts of reduced visions of, the invention, the drum is proerabl'y have a plane or inclined surface, but

supported and secured by supplying a cemopenings form crossf-bars or positioning erititious material irom the interior of themembers arranged between the segments in' drum. Q I an interfitting or interlocking relation.

It is sometimes desirable to provide the The invention will be more clearly underdrum with openin s which have upper or 4 stood from the follewing lescription in conouter partsinto which the bottom or reduced junction with the accompanying drawings portion of the abrasive segment may be in which:

Figurel'is a diagrammatic view of a drum section leadingto the interior of the drum. construction embodying the invention; In certain instances, it may be feasible to Fig. 2 is a sectional view of a portion of rovidethe abrasive segment with an irreguthe drunr taken along a plane perpendicular ar bottom or reduced portion and at the to the airis of the drum of Fig. 1 and with same time provide the lower or reduced part the abrasive segments assembled;

Fig. 3 is a similar sectional view takenof the opening with an irregular or inclined wall. Preferably, .the upper part of the along a plane through the axis of the drum;

opening is provided with an inclined or ir- Fig. 4: is' an isometric view of a portion of regular wall and the bottom or reduced pora modified drum construction;

tion of the abrasive segment is provided with Fig. 5- is a sectionalelevational view of a an irre ular or wedge shaped section. If deportion of the modified construction of Fig.

sired, the corresponding opposite sides of the twith the abrasive segments in position;

upper parts of a series of openings may be -Fig.- 6 is an elevational and view in parremoved forming a single large upper part tial section of a further modification of drunr with a plurality of lower or reduced parts construction; and

leading to the interior of the drum. Fig. 7 is a sectional elevational side view In either case the bottom or reduced porof a portion of the drum construction of tions maybe slightly smaller than the open- Fig. 6. y

ings so that .thesegments may be easily In one embodiment of the invention as '46 dropped or laced within the openings, or illustrated in Figs. 1, 2 and-3 of the drawif desired, t e bottom portion of the reg ings, a hollow drum 10' is rotatably mounted ment may fit relatively close within the upon a shaft-11, and supported thereon by opening. In all cases the segments are 10- means of spokes 12. The drum surface may cated within the openings in an interfitting have a web-like appearance by the provisionor interlocking relation. v of a plurality of appropriately spaced open- In any event, in accordance with the proings 13 having faces 14 and 15, which 'prefvided with openin s which may serve the which may have an irregular shape or surface. dual function of aording means for locat- The openings 13 are so spaced along and ing or looking the abrasive segments on the around the drum that when a properly drum as well as means to permit supplying shaped bottom or reduced ortion of anan appropriate cementitious material from. abrasive segment 16 is place in the openthe interior of the drum for easily and propings, a relatively smooth and substantially erly supporting the segments on the'drum. continuous grinding surface is formed It is preferable to so construct the opening, The abrasive segments 16 may have downand when employing an opening having a wardly depending bottom portions 17 reduced lower part, to"so construct the upadapted to be easily inserted in the openper part of the opening, that the bottom or ings 13-so as to provide sufficient space there: reduced portion of-the abrasive segment will between to permit supplying an appropriate interfit or interlock therewith so as to be cementitious material 18 around the abrasecurely supported to the drain by an approsive segments. .In general, the openings 13 priate cementitious material. are. so shaped and arranged as to serve as Y The wall of each opening and that of the locating or positioning members for proper-- Bottom or reduced portion of each segment ly assembling the segments 16 in an intermay be inclined or ave an irregular shape, tting or interlocking relation therewith. or the wall of the bottom portion of each The opemngs thus servei to securely lock the segments on the drum by cooperation with the supporting cementitious material which may be suppliedfrom the interior of the drum. Preferably, the downwardly depending bottom portion 17 of'each abrasive segment has faces inclined so as to be substantially parallel to v the inwardly inclinedwalls 14 and 15 of the openings 13 when the segments are properly positioned on the drum. The facesor walls of the segments, however, may have an irregular surface or shape. 4 In assembling the abrasive segments on the drum, they may be inverted and placed' small spaces between the abrasive seqments and the drum so as to properly support the segments thereon. When the cementitious material has solidified or hardened sufficiently, the drum is apments placed withinthe openings 13' and properly secured and supported on the drum in the same manner.

This procedure is followed unt il allthe abrasive segments have been assembled on the drum.

In Figs. 4 and 5 I have illustrated a modified form of drum construction. In this construction the drum is mounted in any appropriat'emanner for rotation and is provided with a plurality of properly spaced openings having upper or outer parts 19 into which the bottom or reduced portions of the abrasive segments may be placed or located. Preferably, the upper parts 19 of the openings are provided with inclined walls 20, but it will be understood that these walls may have any desired shapeor configuration,

such as a plane or' irregular surface. The

openings have lower parts or holes 21 proriding communication between the interior of the drum and the upper parts 1;} of the openings topermit supplying an appropriate (fementitious material 18 for properly sup-v.

porting and securing the segments to the drum. The walls or surface of the ldwer parts 21 of the openings may have any'dedesired configuration which may be plane,

inclined or irregular. I The/ abrasive segments are'assembled on this modified form of drum construction in the upper parts 19 of the openings in exactly the, same manner as in the drum -construc- 131011 previously 'described, or in any other appropriate manner. The upper parts 19 of the openings serve as'positioning members for locating the abrasive segments in an in- 'part with a, plurality of lower or reduced parts leading to the interior of the drum,

A drum 22 is suitably mounted; for rotation upon a central shaft (not shown)and is supported thereon by means of central webs 28 and radial webs24. The drum 22 has aniouter cylindrical surface 25 which pref-T erably is shaped fairly accurate. The segments-16 are so shaped that when mounted on the drum they fit rather close to the surface 25 and. form an, outer substantially cylindrical abrasive surface. In order to- ,make a wide wheel, it is preferable to employ more than one row of abrasive segments on the drum and these may be shaped as illustrated to form 'staggeredjoint lines 26 which will minimize the tendency for propriately turned andanother set of seg-- slivers to becarried past in the crevices between the rows of segments.

The bottom portions 17 of the abrasive I segments 16 are adapted to be positioned between or in an interlocking relation with" positioning or locating members 27, which .may be of any desired form but preferably 'arewedge shaped. The positioning memmg members 27 and are relatively large and in the nature of slots. These realtively large upper parts of thewpe'nings each have a plu- 119 rality of lower or reduced parts 28 or holes to permit supplying amappropri'ate cementitious material from the interior of the drum for properly supporting the abrasive segments on the, drum.

It should be notedthatin each of the modifications hereinbefore described, the segments are so formed, ,preferably, that the peripheral lines of contact between adjacent rows of segments are stag ered. .This minimizes the tendency for s'ivers to be carried past in the crevices between the rows of segments. v

I-n service, .pulp wheels are subjected. to varied stresses of large magnitude; and unless the segments are properlysupported and secured upo'nthe drumthey'crack, and the wheel is soon rendered useless. Heretofore, in the manufacture l-of plup wheels no provision has been made for properly .sup- 9 '35 for.

brting the" segments on the drum; and in act, it has been ractically impossible to properly support t e segments on the drum. In accordance with the nvention these difficulties are substantially-eliminated by the provision of means for appropriately sup-. plying .a.. suitable ,cementitious' material around the; abrasive segments. invention" not only simplifies the manufacnature of the whee for grindin wood pulp b.ut,.also, provides a wheel capa le of stand in up under the severe requirements of the p u lp grinding operationfandone which will give long and efiicient service. V Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I

1: A grinding wheel comprising a hollow ro atably mounted drum, abrasive segments th neon, means for locating the abrasive segments on the drum ineoperati ve asso- ClfilI-lOIlrWltl'l openings from the interior of the drum to the abrasive segments, and a cementitious material cooperating with'said locating means for. supporting the segments on the drum. 1

2. A. grindinggalheel comprising a hollow rotatably mounted drum and abrasive segments thereon, the drum having openings 89 each of which have an upper part adapted I for positioning the segments thereon and a lower partoof reduced cross section per mitting supplying an appropriate cem'enti-- tious material'fromthe interior of the drumv supporting the segments properly thereon. 3. A grinding wheel comprising. a rotat- Thus, the

ably mounted drum, abrasive segments thereon, locking members spaced on the drum between .inner reduced portions of ,portions of the segments and permitting ,supplying an appropriate cementitious material from the interior of the drum for properly supporting the segments-;thereon.

5. A grinding wheel comprising a rotatably mounted drum, abrasive segments thereon having bottom portions with inclined walls, the drumhaving openings each bf which have an upper part and a lower part of 'reduced sectionpermitting supplying an appropriate cementitious material from the interior of the drum for properly" supporting the segments thereon, the upper "rnunn Lansson. 

